[scarmig]

Which programmer would you rather hire: the one who memorized a particular algorithm but has no idea how it works, or someone who can develop it from first principles and enlightened judgment?

There's no strong reason to glorify one particular subtraction algorithm over another, especially since the actual use case for it is relatively rare.

[daltonlp]

Full agreement - any subtraction algorithm is fine, as long as it's well-learned (which takes a non-trivial amount of practice).